Transmission medium for ultrasonic diagnosis

ABSTRACT

The present invention provides a transmission medium for ultrasonic diagnosis which comprises a hydrocarbon compound, and/or an ether or ester compound each having a cyclic structure, and has a viscosity of at least 1000 mPa·s at a working temperature. The transmission medium for ultrasonic diagnosis according to the present invention is free from hygroscopicity causing rust generation in a test specimen and worsening the transmission characteristics during use, can impart adhesiveness to a solid within a short period of time, and is particularly excellent in transverse ultrasonic wave transmission, even in a non-contact state in which the test specimen is immersed.

TECHNICAL FIELD

The present invention relates to a transmission medium for ultrasonic diagnosis, and more particularly to a transmission medium for ultrasonic diagnosis characterized in that said transmission medium contains a hydrocarbon, an ether or an ester and has a specific viscosity.

BACKGROUND ART

In recent years, with regard to ultrasonic flaw detection and ultrasonic diagnosis that are one sort of nondestructive inspection, transverse ultrasonic waves have been used in the majority of instances owing to their favorable detection sensitivity. In the case of carrying out the inspection, a highly viscous transmission medium is used between a test specimen and a probe for the purpose of enhancing the transmission efficiency, wherein polyglycerol and polypropylene glycol are known as a transmission medium.

However, the above-mentioned transmission media are problematical in high hygroscopicity causing rust acceleration in a test specimen after use, decrease in the transmission efficiency during use and the like. Under such circumstances the development of a transmission medium with low hygroscopicity has eagerly been desired.

In addition, the conventional polyglycerol and polypropylene glycol have been insufficient in adhesivity to a solid called thixotropics, thereby taking 2 to 3 minutes in sticking and film stabilization. It being so, from the viewpoint of enhancing inspection efficiency and the like, there has been sought for a transmission medium capable of measuring immediately after the coating thereof, that is, a transmission medium having favorable adhesivity to any solid.

Moreover, the aforesaid conventional transmission media are problematical in that it is incapable of transmitting transverse ultrasonic waves in the measurement in a non-contact state in which a test specimen and a probe are immersed therein. Thus it has been hoped to develop a transmission medium capable of transmitting transverse ultrasonic waves even in a non-contact state.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide a transmission medium for ultrasonic diagnosis which is free from hygroscopicity causing rust generation in a test specimen and worsening the transmission characteristics during use, can impart adhesiveness to a solid within a short period of time, and is particularly excellent in transverse ultrasonic wave transmission.

It is another object of the present invention to provide a transmission medium for ultrasonic diagnosis which is excellent in transverse ultrasonic wave transmission even in a non-contact state in which a test specimen is immersed.

As a result of intensive extensive research and investigation accumulated by the present inventor in order to solve the above-mentioned subject, it has been found that a transmission medium for ultrasonic diagnosis which comprises a hydrocarbon compound, and/or an ether or ester compound each having a cyclic structure and has a viscosity of at least 1000 mPa·s at a working temperature is minimized in hygroscopicity and is endowed with excellent transmission characteristics. Thus the present invention has been accomplished on the basis of the foregoing findings and information.

BRIEF DESCRIPTION OF DRAWING

FIG. 1 is a schematic illustration showing a method for evaluating the ultrasonic wave transmission characteristics in the present invention.

THE MOST PREFERRED EMBODIMENT TO CARRY OUT THE INVENTION

The ultrasonic wave as mentioned in the present invention, which means an elastic wave higher than audible frequency range, is a general idea including any of shear horizontal wave (SH wave), shear vertical wave (SV wave) and longitudinal wave (L wave).

It is indispensable that the transmission medium according to the present invention has a viscosity at a working temperature, that is a measurement temperature being at least 1000 mPa·s, preferably in the range of 1,000 to 300,000 mPa·s, more preferably in the range of 1,000 to 150,000 mPa·s. The viscosity thereat, when being lower than 1000 mPa·s, brings bout incapability of transmitting a transverse ultrasonic wave, whereas the viscosity, when being higher than 300,000 mPa·s, leads to inferior handleability due to unreasonably high viscosity, thereby causing difficulties in usage as a transmission medium as the case may be. The hydrocarbon compound to be used in the present invention is not specifically limited provided that the above-mentioned requirement on the viscosity is satisfied, but is preferably a rigid compound having a cyclic structure and/or a quaternary carbon atom.

Specific examples of the above-mentioned hydrocarbon compounds include dipentene oligomer hydride, polybutene, dicyclopentadiene oligomer hydride, dicyclopentadiene-styrene oligomer hydride, polyphenyl ether, styrene oligomer, styrene oligomer hydride, α-methylstyrene oligomer and α-methylstyrene oligomer hydride. Of these, a saturated alicyclic compound is preferable, of which are particularly preferable 2-methyl-3-methyl-2[(3-methylbicyclo[2,2,1]hept-2-yl)methyl]bicyclo[2,2,1]-heptane and 3-methyl-2-[(3-methylbicyclo[2,2,1]hept-2-yl)methyl]-2-[2,3-dimethylbicyclo-[2,2,1]hept-2-yl]methyl]bicyclo[2,2,1]heptane.

In addition, it is indispensable that the ether or ester in the present invention satisfies the requirement on the viscosity and at the same time, has a cyclic structure. The reason for this is that the compound having a flexible structure free from a cyclic structure is inferior in transverse ultrasonic wave transmission characteristics.

Specific examples of the above-mentioned cyclic structure include saturated rings such as cyclohexane ring, decalin ring, cyclopentane ring, bicyclo[2,2,1]heptane ring, bicyclo[2,2,2]octane ring, bicyclo[3,2,1]octane ring and bicyclo[3,3,0]octane, and aromatic rings such as benzene ring, naphthalene ring, anthracene ring, fluorene ring, indan ring and acenaphthene ring.

In the case where the above-exemplified compound has extremely high viscosity, or is in the form of a resin, it may be mixed with a mixing base material such as a paraffin base hydrocarbon and/or an ester compound. The mixing ratio, which may be arbitrarily selected within the scope that the requirement on the viscosity is satisfied by the mixing, is in the range of usually 1 to 95% by mass, preferably 5 to 80% by mass.

In what follows, the present invention will be described in more detail with reference to working examples, which however shall never limit the present invention thereto.

{Method for Evaluating Ultrasonic Wave Transmission Characteristics}

FIG. 1 is a schematic illustration showing a method for evaluating the ultrasonic wave transmission characteristics in the present invention.

Opposed type probes for a shear horizontal wave(SH wave) and for a longitudinal wave (L wave) were adhesively fixed onto a test specimen made of stainless steel SUS 304 at a constant stress (13 MPa). Subsequently, any of the transmission media in examples and comparative examples was applied as a coating to the interface between the SH probe and the SUS 304, and a measurement was made of the reception sensitivity (V) at room temperature (25° C.) by the use of SH wave and L wave each having a frequency of 5 MHz. A ultrasonic diagnosis instrument (manufactured by Toshiba Tungaloy Co.,Ltd. under the trade name “USH-B”) was used for the transmission and reception of ultrasonic waves and the analysis of the waveform.

EXAMPLE 1

In a 2 liter autoclave made of stainless steel were placed 561 g (8 mol) of crotonaldehyde and 352 g (2.67 mol) of dicyclopentadiene to proceed with reaction at 170° C. for 3 hours. After cooling the reaction product, the autoclave was charged with 18 g of Raney nickel catalyst (manufactured by Kawaken Fine Chemicals Co.,Ltd. under the trade name “M-300T”) to carry out hydrogenation at a hydrogen pressure of 9 kg/cm² at a reaction temperature of 150° C. for 4 hours. After cooling the reaction product the catalyst was filtered away, and the resultant filtrate was distilled under reduced pressure, so that 565 g of distillate of 105° C./20 mmHg was obtained. Through the analysis by means of mass spectrometric spectrum and nuclear magnetic resonance spectrum, the resultant distillate was identified as 2-hydroxymethylbicyclo[2,2,1]heptane.

Subsequently, 20 g of γ-alumina (manufactured by Nikki Chemical Co., Ltd. under the trade name “N612N”) was placed in a flow system atmospheric pressure tubular reactor made of quartz glass measuring 20 mm in outside diameter and 500 mm in length, so that dehydration reaction was put into practice at a reaction temperature of 285° C. at a weight hourly space velocity (WHSV) of 1.1 hr⁻¹. As a result, there was obtained a dehydrated reaction product of 2-hydroxymethyl-3-methylbicyclo[2,2,1]heptane which contained both 2-methylene-3-methylbicyclo[2,2,1]heptane and 2,3-dimethylbicyclo[2,2,1]hept-2-ene.

Subsequently, in a 500 milliliter four-necked flask were placed 4.0 g of trifluoroboron diethyl ether complex and 200 g of the olefin compound obtained in the above-mentioned procedure, and the resultant mixture was subjected to oligomerizing reaction at 20° C. for 6 hours under stirring by the use of a mechanical stirrer. The resultant reaction mixture was washed with dilute aqueous solution of sodium hydroxide and saturated common salt water and then, was hydrogenated in a one liter autoclave, while adding therein 6.0 g of a nickel /diatomaceous earth-based hydrogenation catalyst (manufactured by Nikki Chemical Co., Ltd. under the trade name “N-113”). The hydrogenation was carried out under the conditions including a hydrogen pressure of 3 MPa, a reaction temperature of 250° C. and a reaction time of 5 hours. After the completion of the reaction, the catalyst was removed by means of filtration, and the resultant filtrate was distilled under reduced pressure. As a result, there were obtained 145 g of 2-methyl-3-methyl-2[(3-methylbicyclo[2,2,1]hept-2-yl)methyl]bicyclo-[2,2,1]heptane as a 1333 Pa distillate having a boiling point of 160 to 163° C. (hereinafter referred to as “Fluid 1”), and 30 g of 3-methyl-2-[(3-methylbicyclo[2,2,1]hept-2-yl)methyl]-2-[2,3-dimethylbicyclo-[2,2,1]hept-2-yl)methyl]bicyclo[2,2,1]heptane as a 1333 Pa distillate having a boiling point of 240 to 250° C. (hereinafter referred to as “Fluid 2”).

An evaluation was made of ultrasonic wave transmission characteristics of a mixture of the Fluid 2 (79% by weight) and the Fluid 1 (21% by weight) as the transmission medium. The results are given in Table 1.

EXAMPLES 2 TO 12 AND COMPARATIVE EXAMPLES 1 to 7

There were prepared the samples each comprising the substances and having mixing proportion as given in Table 1, and evaluations were made of ultrasonic wave transmission characteristics of each of the mixtures as the transmission medium. The results are given in Table 1.

As a result, the transmission medium for ultrasonic diagnosis according to the present invention has high reception sensitivity for transverse ultrasonic waves and at the same time, has reception sensitivity for longitudinal ultrasonic waves which is comparable to that of conventional glycerol based transmission media.

COMPARATIVE EXAMPLE 8

Evaluations were made of ultrasonic wave transmission characteristics of polyglycerol based transmission medium available on the market immediately after coating and 5 minutes after coating. The results are given in Table 1.

The polyglycerol based transmission medium available on the market revealed marked deterioration in reception sensitivity with the lapse of time.

EXAMPLE 13

Evaluations were made of ultrasonic wave transmission characteristics of the transmission medium same as in Example 1, 5 minutes after coating.

As a result, no deterioration in reception sensitivity was observed with the lapse of time. TABLE 1-1 Substance Example No. (wight %) 1 2 3 4 5 6 7 8 9 10 11 12 Fluid 1 21 40 50 50 55 60 Fluid 2 79 100 78 Mineral oil*¹ 22 56 Hydrogenated 60 50 44 48 turpentine resin*² Hydrogenated 50 45 40 petroleum resin*³ Hydrogenated 52 dipentene dimer*⁴ Polybutene*⁵ 100 Polyphenyl 100 ether*⁶ Viscosity 12000 200000 8500 200000 18500 65000 16000 5700 8400 55000 21000 1200 (mPa · s @25° C.) Reception 0.88 1.66 0.55 0.97 0.67 0.51 0.25 0.11 0.54 0.76 0.53 0.12 sensitivity for SH wave(V) Reception 0.26 0.11 0.27 0.12 0.26 0.06 0.07 0.11 0.17 0.13 0.11 0.68 sensitivity for L wave (V) {Remarks} *¹paraffin base mineral oil P-500 *²manufactured by Yasuhara Chemical Co., Ltd. under trade name “Clearon P-85” *³manufactured by Idemitsu Petrochemical Co., Ltd. under the trade name “Aimarb P100” *⁴manufactured by Yasuhara Chemical Co., Ltd. under the trade name “YS OilDH” *⁵manufactured by Idemitsu Petrochemical Co., Ltd. under the trade name “Polybutene 100H” *⁶manufactured by Matsumura Oil Research Corporation under the trade name “Polyphenyl ether 5P4E”

TABLE 1-2 Comparative Example No. Example 8 13 (5 min (5 min after after Substance(weight %) 1 2 3 4 5 6 7 8 coating) coating) Silicone oil*⁷ 100 Silicone oil*⁸ 100 Silicone oil*⁹ 100 Silicone oil*¹⁰ 100 Fluid 1 50 21 Fluid 2 50 79 Polypropylene glycol*¹¹ 100 Mineral oil*¹ 100 Polyglycerol 100 100 Viscosity (mPa · s @25° C.) 5000 10000 30000 100000 530 650 220 140000 140000 12000 Reception sensitivity for SH wave (V) 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.99 0.67 0.88 Reception sensitivity for L wave (V) 0.01 0.03 0.01 0.01 0.52 0.23 0.46 0.46 0.34 0.26 {Remarks} *⁷manufactured by Toray Silicone Co., Ltd. under the trade name “Silicone Oil SH200-5000cs” *⁸manufactured by Toray Silicone Co., Ltd. under the trade name “Silicone Oil SH200-10000cs” *⁹manufactured by Toray Silicone Co., Ltd. under the trade name “Silicone Oil SH200-30000cs” *¹⁰manufactured by Toray Silicone Co., Ltd. under the trade name “Silicone Oil SH200-100000cs” *¹¹Polypropylene glycol, triol type, manufactured by Wako Pure Chemical Industries Co., Ltd.

INDUSTRIAL APPLICABILITY

The transmission medium for ultrasonic waves according to the present invention is a transmission medium for ultrasonic diagnosis which is free from hygroscopicity causing rust generation in a test specimen and worsening the transmission characteristics during use, can impart adhesiveness to a solid within a short period of time, and is particularly excellent in ultrasonic wave transmission even in a non-contact state in which a test specimen is immersed. The transmission medium according to the present invention, which can be used for both transverse ultrasonic waves and longitudinal ultrasonic waves, is particularly excellent in the transmission of transverse ultrasonic waves, and as a result, is effectively utilizable for ultrasonic flaw detection, ultrasonic measurement and instrumentation and the like. 

1. A transmission medium for ultrasonic diagnosis which comprises a hydrocarbon compound, and optionally an ether or an ester compound, wherein the ether and the ester has a cyclic structure, and wherein said transmission medium has a viscosity of at least 1000 mPa·s at a working temperature.
 2. The transmission medium for ultrasonic diagnosis according to claim 1, wherein the hydrocarbon compound has a cyclic structure and/or a quaternary carbon atom.
 3. The transmission medium for ultrasonic diagnosis according to claim 1, wherein ultrasonic waves for the ultrasonic diagnosis are transverse ultrasonic waves.
 4. The transmission medium for ultrasonic diagnosis according to claim 2, wherein ultrasonic waves for the ultrasonic diagnosis are transverse ultrasonic waves.
 5. The transmission medium for ultrasonic diagnosis according to claim 1, wherein said viscosity is in the range of 1,000 to 300,000 mPa·s.
 6. The transmission medium for ultrasonic diagnosis according to claim 1, wherein said viscosity is in the range of 1,000 to 150,000 mPa·s.
 7. The transmission medium for ultrasonic diagnosis according to claim 1, wherein the hydrocarbon is selected from a group consisting of dipentene oligomer hydride, polybutene, dicyclopentadiene oligomer hydride, dicyclopentadiene-styrene oligomer hydride, polyphenyl ether, styrene oligomer, styrene oligomer hydride, α-methylstyrene oligomer, α-methylstyrene oligomer hydride, and mixtures thereof.
 8. The transmission medium for ultrasonic diagnosis according to claim 1, wherein the hydrocarbon is selected from a group consisting of 2-methyl-3-methyl-2-[(3-methylbicyclo[2,2,1]hept-2-yl)methyl]bicyclo[2,2,1]-heptane, 3-methyl-2-[(3-methylbicyclo[2,2,1]hept-2-yl)methyl]-2-[2,3-dimethylbicyclo-[2,2,1]hept-2-yl]methyl]bicyclo[2,2,1]heptane, and mixtures thereof. 